Author: Gabriel Petcu

Student number: 984159

Aim (aim):

A map representation of an ancient city with the oldest locations.

Visual Design Type (vistype):

World projection with dots.

Visual Mappings (vismapping):

Points are represented depending on latitude and longitude

Tooltip to see the oldest date along with period names

Highlighting all other points with the same oldest date.

Data Preparation (dataprep):

I have sorted the data set depending on the minimum date. And took all the data that had the minimum date < -400 Improvements (improvements):

It's hard to determine each location as there are a lot of settlements(e.g. Italy) An improvement could be to make the map zoomable

import altair as alt
import pandas as pd
from vega_datasets import data

# data generators for background
sphere = alt.sphere()
graticule = alt.graticule()

#import data and map
alt.data_transformers.disable_max_rows()
source = alt.topo_feature(data.world_110m.url, 'countries')
data = pd.read_csv('Prehistory.csv')

background = alt.Chart(source).mark_geoshape(
    fill='lightgray',
    stroke='black'
).project(
    type= 'mercator', 
    center = [10,40],
    scale=500,
    ).properties(
    title='Oldest settlements in prehistory',
    width=800,
    height=600,
)

highlight = alt.selection_single(on='mouseover', fields=['minDate'], empty='none')

points = alt.Chart(data).mark_circle(
    size=9,
    color='steelblue'
).encode(
    longitude='reprLong:Q',
    latitude='reprLat:Q',
    tooltip=[alt.Tooltip
             ('featureType', title="Type of settlement"),
             alt.Tooltip
             ('reprLong', title="Longitudinal coordinate"),
             alt.Tooltip
             ('reprLat', title="Latitudinal coordinate"),
             alt.Tooltip
             ('description', title="description"),
             alt.Tooltip
             ('minDate', title="Starting year")
            ],
    color=alt.condition(highlight, alt.value('red'),
                        'minDate:Q',
                        title = "Starting year",
                        scale=alt.Scale(scheme='greens'))
).add_selection(
    highlight
).project(
    scale = 500,
    center = [10,40],
    
)



    

background + points